1. Field of the Invention
This invention relates to a system and method of transmitting data in a lithographic device.
2. Background Information
A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In that instance, a patterning device, which is alternatively referred to as a mask or a reticle, may be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (e.g. comprising part of, one, or several dies) on a substrate (e.g. a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate.
In general, a single substrate will contain a network of adjacent target portions that are successively patterned. Known lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at one time, and so-called scanners, in which each target portion is irradiated by scanning the pattern through a radiation beam in a given direction (the “scanning”-direction) while synchronously scanning the substrate parallel or anti parallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.
A lithographic apparatus may include several sensors to monitor conditions within the apparatus such as local temperature and received light. The sensors are typically coupled to an electronic rack outside the apparatus, wherein the rack may include one or more cards inserted into one or more backplanes. Lithographic devices typically use an analog signal path to couple the sensors to the electronic rack.
As extreme ultraviolet (EUV) lithography develops, problems arise that are related to the vacuum environment in which EUV exposure is performed. In a vacuum, cables give rise to outgassing, which may cause contamination of the vacuum, potentially leading to problems such as fouling of optical elements. Another problem associated with the operation of electronics in a vacuum is the lack of an atmosphere to support conductive heat transfer, which may complicate the use of heat-generating circuit elements.
In a sensor bus, reliability and support for real-time operation may also be desired.